：The discharge performance of the screen filter determines the water consumption in the discharge process of the filter and the working efficiency in the next work cycle. Based on the analysis of the discharge performance of the screen filter, it is found that the sewage discharge flow and the sediment content of the inlet water are the important influencing factors. For exploring screen filter drainage effect, the focus of the experiment was on the relationship of sewage discharge cleanliness, sewage discharge time, sewage discharge flow and sediment content of a new type of rotatable plate screen filter .The results show that: the best default under differential pressure and sewage discharge flow is the core of the rotatable plate net filter factors, with the increase of sewage discharge flow, sewage discharge time reduces, sewage discharge cleanliness increases, blow down effect is remarkable. At the same time, according to the law of mass conservation, the mathematical models of sewage discharge time and sewage discharge flow, sewage discharge cleanliness and sewage discharge flow were established. According to the test results, the results show that the fitting correlation coefficient r between the calculated results and the test results can reach above 0.98 .In order to ensure that the filter can achieve high efficiency in the case of low discharge water consumption, it is recommended to set the sewage discharge flow as 180 m 3 /h and the sewage discharge time as 50 s in actual work to achieve 98% of the sewage discharge cleanliness. Key words：rotatable plate screen filter；sewage discharge time；sewage discharge cleanliness；sewage discharge flow；effect of sewage